A method for extracting uranium and thorium elements

Abstract

The present invention discloses a method for extracting uranium and thorium elements, belonging to the technical field of rare earth liquid treatment. The method includes mixing an alkyl phenyl oxovaleric acid extractant with an organic solvent to obtain an organic phase; mixing the organic phase with a rare earth solution containing uranium and thorium elements for extraction, so that the rare earth remains in the aqueous phase and the uranium and thorium elements enter the organic phase. This method has fewer extraction stages, a simple process, good separation effect, and high extraction rates of uranium and thorium.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth liquid treatment, and particularly relates to a method for extracting uranium and thorium elements. Background Art

[0002] Since rare earth ores contain some radioactive elements, the rare earth leaching solution contains a small amount of radioactive elements uranium and thorium, where the uranium concentration is 10 - 30 mg / L and the thorium concentration is 5 - 30 mg / L, and the total radioactivity of the leaching solution is relatively high; these radioactive elements are further dispersed during the separation process, resulting in an increase in the area of radioactive contamination in the production environment, and further increasing the difficulty of treating these radioactive elements. Therefore, corresponding treatment schemes for the radioactive hazards in the rare earth separation process need to be proposed from the perspective of radiological health protection or environmental protection, deeply enrich the radioactive elements, and reduce the distribution of radioactive elements in the extraction and separation process, which is beneficial to improving the production environment.

[0003] Currently, the method for separating uranium and thorium from rare earth liquid is to dissolve monazite uranium and thorium slag with hydrochloric acid, extract uranium with P350 extractant, and then adjust the acidity to extract thorium. After separating uranium and thorium from the rare earth leaching solution respectively by this method, the residual uranium and thorium elements in the rare earth leaching solution are still relatively high. Summary of the Invention

[0004] In order to solve the problems of the prior art, the present invention provides a method for extracting uranium and thorium elements, including:

[0005] Mix an alkyl phenyl oxovaleric acid extractant with an organic solvent to obtain an organic phase;

[0006] Mix the organic phase with a rare earth solution containing uranium and thorium elements for extraction, so that rare earth remains in the aqueous phase, and uranium and thorium elements enter the organic phase.

[0007] Further, the alkyl phenyl oxovaleric acid extractant includes one or more of the compounds with the structure of formula (I):

[0008]

[0009] Wherein, R is selected from alkyl groups of C1 - C10.

[0010] Further, the organic solvent is selected from one or more of aviation kerosene, hydrogenated solvent kerosene, toluene, and xylene.

[0011] Further, the pH value of the rare earth solution containing uranium and thorium elements is 0.1 - 7.

[0012] Further, the alkyl phenyl oxovaleric acid extractant and the organic solvent are mixed according to a weight ratio of 1:(0.1 - 10).

[0013] Further, the organic phase and the rare earth solution containing uranium and thorium elements are mixed at a volume ratio of 1:(0.1 - 100).

[0014] Further, the synthesis method of the alkylphenyl oxopentanoic acid extractant is as follows:

[0015] Add glutaric anhydride to anhydrous aluminum trichloride, mix and stir to obtain a mixture;

[0016] Add alkylbenzene to the mixture, continue stirring and reacting to obtain a reaction solution;

[0017] Slowly add deionized water to the reaction solution and stir. After standing, it is separated into an oil phase and an aqueous phase, and the oil phase is separated;

[0018] Distill the oil phase under reduced pressure to obtain the alkylphenyl oxopentanoic acid.

[0019] Further, the weight ratio of the alkylbenzene, glutaric anhydride and the anhydrous aluminum trichloride is 0.8 - 10:1:1 - 10.

[0020] Further, after adding alkylbenzene to the mixed solution, stir and react at a temperature of 25 - 125 °C for 10 - 300 min to obtain the reaction solution.

[0021] Further, distill the oil phase under reduced pressure at 50 - 145 °C to obtain the alkylphenyl oxopentanoic acid.

[0022] The beneficial effects brought by the technical solution provided by the embodiment of the present invention are as follows: The synthesis of the alkylphenyl oxopentanoic acid extractant is simple and the cost is low. Using the extractant to extract uranium and thorium elements, the number of extraction stages is small, the process is simple, the separation effect is good, and the extraction rates of uranium and thorium are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a flowchart of a method for extracting uranium and thorium elements provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0025] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the description of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention.

[0026] Example 1

[0027] A method for extracting uranium and thorium elements, see Figure 1 , the method specifically includes the following steps:

[0028] Step (101): Mix an alkylphenyl oxopentanoic acid extractant with an organic solvent to obtain an organic phase.

[0029] It should be noted that the alkylphenyl oxopentanoic acid extractant includes one or more of the compounds with the structure of formula (I):

[0030]

[0031] Among them, R is selected from alkyl groups with 1 to 10 carbon atoms or haloalkyl groups.

[0032] The organic solvent is selected from one or more of aviation kerosene, hydrogenated solvent kerosene, toluene, and xylene.

[0033] Step (102): Mix the organic phase with a rare earth solution containing uranium and thorium elements for extraction, so that the rare earth remains in the aqueous phase, and the uranium and thorium elements enter the organic phase.

[0034] It is worth mentioning that this method has few extraction stages, a simple process, good separation effect, and high extraction rates of uranium and thorium.

[0035] Example 2

[0036] A method for extracting uranium and thorium elements, the specific steps include:

[0037] Step (201): Mix a methylphenyl oxopentanoic acid extractant with aviation kerosene according to a weight ratio of 1:0.1 to obtain 100 mL of an organic phase.

[0038] It should be noted that the preparation method of methylphenyl oxopentanoic acid can be as follows: In a 250 mL single-neck flask, add 20 g of glutaric anhydride and 20 g of anhydrous aluminum trichloride, mix and stir evenly to obtain a mixture; add 16 g of toluene to the mixture, continue stirring, keep the reaction temperature at 25 °C, and react for 10 min to obtain a reaction solution; slowly add 250 mL of deionized water to the reaction solution and stir, and after standing, it is divided into an oil phase and an aqueous phase, and the oil phase is separated; the oil phase is distilled under reduced pressure at 50 °C to obtain the product methylphenyl oxopentanoic acid. Through acid-base titration and nuclear magnetic resonance detection, the purity of methylphenyl oxopentanoic acid is 98%, and the yield is 94%.

[0039] Step (202): Mix 100 mL of the organic phase with 10 mL of a rare earth solution with a pH value of 0.1 containing uranium and thorium elements for extraction, so that the rare earth remains in the aqueous phase, and the uranium and thorium elements enter the organic phase.

[0040] It should be noted that in the rare earth solution containing uranium and thorium elements, the contents of uranium and thorium elements are 50 mg / L and 180 mg / L respectively, and the total concentration of rare earth elements is 1.8 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 1.5 mg / L and 3.2 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.0% and 98.2% respectively.

[0041] Example 3

[0042] A method for extracting uranium and thorium elements, the specific steps include:

[0043] Step (301): Mix the ethyl phenyl oxovaleric acid extractant and hydrogenated solvent kerosene according to a weight ratio of 1:4 to obtain 100 mL of organic phase.

[0044] It should be noted that the preparation method of ethyl phenyl oxovaleric acid can be as follows: In a 250 mL single-neck flask, add 20 g of glutaric anhydride and 65 g of anhydrous aluminum trichloride, mix and stir evenly to obtain a mixture; add 36 g of ethylbenzene to the mixture, continue stirring, keep the reaction temperature at 35 °C, and react for 30 min to obtain a reaction solution; slowly add 250 mL of deionized water to the reaction solution and stir, and after standing, it is divided into an oil phase and an aqueous phase, and the oil phase is separated; the oil phase is subjected to vacuum distillation at 75 °C to obtain the product ethyl phenyl oxovaleric acid. Through acid-base titration and nuclear magnetic resonance detection, the purity of ethyl phenyl oxovaleric acid is 98% and the yield is 94%.

[0045] Step (302): Mix 100 mL of the organic phase with 20 mL of a rare earth solution containing uranium and thorium elements with a pH value of 1 for extraction, so that the rare earth remains in the aqueous phase and the uranium and thorium elements enter the organic phase.

[0046] It should be noted that in the rare earth solution containing uranium and thorium elements, the contents of uranium and thorium elements are 625 mg / L and 2250 mg / L respectively, and the total concentration of rare earth elements is 2.5 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 17.5 mg / L and 40.0 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.2% and 98.2% respectively.

[0047] Example 4

[0048] A method for extracting uranium and thorium elements, the specific steps include:

[0049] Step (401): Mix the isopropyl phenyl oxovaleric acid extractant and toluene according to a weight ratio of 1:4 to obtain 100 mL of organic phase.

[0050] It should be noted that the preparation method of isopropylphenyl oxopentanoic acid can be as follows: In a 250 mL single-necked flask, add 20 g of glutaric anhydride and 70 g of anhydrous aluminum trichloride, mix and stir evenly to obtain a mixture; add 55 g of cumene to the mixture, continue to stir, maintain the reaction temperature at 25 °C, and react for 30 min to obtain a reaction solution; slowly add 250 mL of deionized water to the reaction solution and stir, let it stand and separate into an oil phase and an aqueous phase, and separate out the oil phase; distill the oil phase under reduced pressure at 85 °C to obtain the product isopropylphenyl oxopentanoic acid. Through acid-base titration and nuclear magnetic resonance detection, the purity of isopropylphenyl oxopentanoic acid is 97%, and the yield is 93%.

[0051] Step (402): Mix 100 mL of the organic phase with 2500 mL of a rare earth solution containing uranium and thorium elements with a pH value of 2 for extraction, so that the rare earth remains in the aqueous phase, and the uranium and thorium elements enter the organic phase.

[0052] It should be noted that the contents of uranium and thorium elements in the rare earth solution containing uranium and thorium elements are 5 mg / L and 18 mg / L respectively, and the total concentration of rare earth elements is 1.2 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 0.13 mg / L and 0.31 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.4% and 98.27% respectively.

[0053] Example Five

[0054] A method for extracting uranium and thorium elements, the specific steps include:

[0055] Step (501): Mix the isobutylphenyl oxopentanoic acid extractant with xylene according to a weight ratio of 1:9 to obtain 100 mL of an organic phase.

[0056] It should be noted that the preparation method of isobutylphenyl oxopentanoic acid can be as follows: In a 250 mL single-necked flask, add 20 g of glutaric anhydride and 150 g of anhydrous aluminum trichloride, mix and stir evenly to obtain a mixture; add 55 g of isobutylbenzene to the mixture, continue to stir, maintain the reaction temperature at 25 °C, and react for 30 min to obtain a reaction solution; slowly add 250 mL of deionized water to the reaction solution and stir, let it stand and separate into an oil phase and an aqueous phase, and separate out the oil phase; distill the oil phase under reduced pressure at 110 °C to obtain the product isobutylphenyl oxopentanoic acid. Through acid-base titration and nuclear magnetic resonance detection, the purity of isobutylphenyl oxopentanoic acid is 97%, and the yield is 93%.

[0057] Step (502): Mix 100 mL of the organic phase with 2500 mL of a rare earth solution containing uranium and thorium elements with a pH value of 3 for extraction, so that the rare earth remains in the aqueous phase, and the uranium and thorium elements enter the organic phase.

[0058] It should be noted that the contents of uranium and thorium elements in the rare earth solution containing uranium and thorium elements are 5 mg / L and 18 mg / L respectively, and the total concentration of rare earth elements is 1.2 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 0.15 mg / L and 0.31 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.0% and 98.27% respectively.

[0059] Example VI

[0060] A method for extracting uranium and thorium elements, the specific steps include:

[0061] Step (601): Mix the octylphenyl oxovaleric acid extractant with a mixture of toluene and xylene in a weight ratio of 1:10 to obtain 100 mL of organic phase.

[0062] It should be noted that the preparation method of octylphenyl oxovaleric acid can be: in a 250 mL single-necked flask, add 20 g of glutaric anhydride and 200 g of anhydrous aluminum trichloride, mix and stir evenly to obtain a mixture; add 100 g of octylbenzene to the mixture, continue to stir, keep the reaction temperature at 25 °C, and react for 30 min to obtain a reaction solution; slowly add 250 mL of deionized water to the reaction solution and stir, and after standing, it is divided into an oil phase and an aqueous phase, and the oil phase is separated; the oil phase is distilled under reduced pressure at 135 °C to obtain the product octylphenyl oxovaleric acid. After acid-base titration and nuclear magnetic resonance detection, the purity of octylphenyl oxovaleric acid is 95% and the yield is 92%.

[0063] Step (602): Mix 100 mL of the organic phase with 2500 mL of a rare earth solution containing uranium and thorium elements with a pH value of 4 for extraction, so that the rare earth remains in the aqueous phase and the uranium and thorium elements enter the organic phase.

[0064] It should be noted that the contents of uranium and thorium elements in the rare earth solution containing uranium and thorium elements are 5 mg / L and 18 mg / L respectively, and the total concentration of rare earth elements is 1.2 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 0.15 mg / L and 0.30 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.0% and 98.3% respectively.

[0065] Example VII

[0066] A method for extracting uranium and thorium elements, the specific steps include:

[0067] Step (701): Mix the decylphenyl oxovaleric acid extractant with a mixture of toluene, xylene, and aviation kerosene at a weight ratio of 1:10 to obtain 100 mL of the organic phase.

[0068] It should be noted that the preparation method of decylphenyl oxovaleric acid can be as follows: In a 250 mL single-necked flask, add 20 g of glutaric anhydride and 200 g of anhydrous aluminum trichloride, mix and stir evenly to obtain a mixture; add 200 g of decylbenzene to the mixture, continue stirring, maintain the reaction temperature at 125 °C, and react for 300 min to obtain a reaction solution; slowly add 250 mL of deionized water to the reaction solution and stir, and after standing, it is divided into an oil phase and an aqueous phase, and the oil phase is separated; the oil phase is distilled under reduced pressure at 145 °C to obtain the product decylphenyl oxovaleric acid. After acid-base titration and nuclear magnetic resonance detection, the purity of decylphenyl oxovaleric acid is 92% and the yield is 90%.

[0069] Step (702): Mix 100 mL of the organic phase with 10,000 mL of a rare earth solution containing uranium and thorium elements with a pH value of 5 for extraction, so that the rare earth remains in the aqueous phase and the uranium and thorium elements enter the organic phase.

[0070] It should be noted that the contents of uranium and thorium elements in the rare earth solution containing uranium and thorium elements are 1.25 mg / L and 4.5 mg / L respectively, and the total concentration of rare earth elements is 0.30 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 0.035 mg / L and 0.075 mg / L respectively. The results show that the extraction rates of this extractant for uranium and thorium elements reach 97.2% and 98.3% respectively.

[0071] Example Eight

[0072] A method for extracting uranium and thorium elements, the specific steps include:

[0073] Step (801): Mix the mixture of decylphenyl oxovaleric acid extractant and octylphenyl oxovaleric acid extractant with a mixture of toluene, xylene, and aviation kerosene at a weight ratio of 1:10 to obtain 100 mL of the organic phase.

[0074] It should be noted that decylphenyl oxovaleric acid can be prepared according to the method in Example Seven, and octylphenyl oxovaleric acid can be prepared according to the method in Example Six.

[0075] Step (802): Mix 100 mL of the organic phase with 2500 mL of a rare earth solution containing uranium and thorium elements with a pH value of 6 for extraction, so that the rare earth remains in the aqueous phase and the uranium and thorium elements enter the organic phase.

[0076] It should be noted that the contents of uranium and thorium elements in the rare earth solution containing uranium and thorium elements are 5 mg / L and 18 mg / L respectively, and the total concentration of rare earth elements is 1.2 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 0.11 mg / L and 0.29 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.8% and 98.4% respectively.

[0077] Example 9

[0078] A method for extracting uranium and thorium elements, the specific steps include:

[0079] Step (901): Mix a mixture of isobutyl phenyl oxovaleric acid extractant, decyl phenyl oxovaleric acid extractant and octyl phenyl oxovaleric acid extractant with a mixture of toluene, xylene and aviation kerosene according to a weight ratio of 1:10 to obtain 100 mL of organic phase.

[0080] It should be noted that isobutyl phenyl oxovaleric acid can be prepared according to the method in Example 5, decyl phenyl oxovaleric acid can be prepared according to the method in Example 7, and octyl phenyl oxovaleric acid can be prepared according to the method in Example 6.

[0081] Step (902): Mix 100 mL of the organic phase with 2500 mL of a rare earth solution containing uranium and thorium elements with a pH value of 7 for extraction, so that the rare earth remains in the aqueous phase and the uranium and thorium elements enter the organic phase.

[0082] It should be noted that the contents of uranium and thorium elements in the rare earth solution containing uranium and thorium elements are 5 mg / L and 18 mg / L respectively, and the total concentration of rare earth elements is 1.2 mol / L. After extraction and determination by ICP-OES, the contents of residual uranium and thorium elements in the aqueous phase are 0.14 mg / L and 0.30 mg / L respectively. The results show that the extraction rates of uranium and thorium elements by this extractant reach 97.2% and 98.3% respectively.

[0083] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments.

[0084] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for extracting uranium and thorium elements, characterized in that, Comprising: Mixing an alkylphenyl oxopentanoic acid extractant with an organic solvent to obtain an organic phase; mixing the organic phase with a rare earth solution containing uranium and thorium elements for extraction, leaving the rare earth in the aqueous phase and allowing the uranium and thorium elements to enter the organic phase; The alkylphenyl oxopentanoic acid extractant comprises one or more of the compounds having the structure of formula (I): ； Wherein, R is selected from alkyl groups having 1 to 10 carbon atoms; The pH value of the rare earth solution containing uranium and thorium elements is 0.1 to 7.

2. A method for extracting uranium and thorium elements according to claim 1, characterized in that, The organic solvent is selected from one or more of aviation kerosene, hydrogenated solvent kerosene, toluene, and xylene.

3. A method for extracting uranium and thorium elements according to claim 1, characterized in that, The alkylphenyl oxopentanoic acid extractant and the organic solvent are mixed in a weight ratio of 1:0.1 to 10.

4. A method for extracting uranium and thorium elements according to claim 1, characterized in that, The organic phase and the rare earth solution containing uranium and thorium elements are mixed in a volume ratio of 1:0.1 to 100.

5. A method for extracting uranium and thorium elements according to claim 1, characterized in that, The synthesis method of the alkylphenyl oxopentanoic acid extractant is as follows: adding glutaric anhydride to anhydrous aluminum trichloride, mixing and stirring to obtain a mixture; adding alkylbenzene to the mixture and continuing to stir and react to obtain a reaction solution; slowly adding deionized water to the reaction solution and stirring, standing to separate into an oil phase and an aqueous phase, and separating out the oil phase; subjecting the oil phase to vacuum distillation to obtain the alkylphenyl oxopentanoic acid.

6. A method for extracting uranium and thorium elements according to claim 5, characterized in that, The weight ratio of the alkylbenzene, glutaric anhydride, and the anhydrous aluminum trichloride is 0.8 to 10:1:1 to 10.

7. A method for extracting uranium and thorium elements according to claim 6, characterized in that, After adding alkylbenzene to the mixture, stirring and reacting at a temperature of 25 to 125 °C for 10 to 300 min to obtain the reaction solution.

8. A method for extracting uranium and thorium elements according to claim 7, characterized in that, Subjecting the oil phase to vacuum distillation at 50 to 145 °C to obtain the alkylphenyl oxopentanoic acid.

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